1. Field of the Invention
The present invention relates to an automated robot cleaner, and more particularly, to a robot cleaner, a system employing the same and a method for re-connecting the robot cleaner to an external recharging device efficiently.
2. Description of the Related Art
Generally, a robot cleaner sucks dust or foreign substances from a cleaning surface. The robot cleaner performs a cleaning operation while automatically running on a cleaning area without manipulation by a user.
Since the robot cleaner regularly checks the locations and measures distances to obstacles like furniture, office appliances and walls, the robot cleaner can clean the cleaning area while not colliding with any of the obstacles.
Such a robot cleaner is equipped with a battery, which supplies the power required for the robot cleaner to run. The battery may be recharged by an external recharging device.
Accordingly, when the battery needs recharging, the robot cleaner has to locate the external recharging device and return to the external recharging device for recharging, automatically.
For this purpose, the robot cleaner usually uses a high frequency signal that is received from the external recharging device to detect the location of the external recharging device.
This way, however, has some shortcomings in that the level of high frequency signal can be varied by external factors such as reflective waves and/or interference waves, and by the variation of the high frequency signal level. These different factors will cause the robot cleaner to not find the exact location needed to dock with the external recharging device.